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树木固氮是森林土壤氮素的重要来源,许多固氮树种能在瘠薄的土壤上生长,对土壤的改良起着重要作用;在混交林中作伴生树种有效地促进主林木的生长;农区常用它作有机肥源,调节氮素的供需平衡,促进农业增产。固氮树种的研究和利用逐渐引起人们的重视(Bo-nd,1976;Sprent,1979)。紫色土是四川盆地的主要土类,该区森林植被覆盖率低,水土
Nitrogen fixation of trees is an important source of nitrogen in forest soils. Many nitrogen-fixing species can grow on barren soil and play an important role in soil improvement. Associated tree species in mixed forest can effectively promote the growth of main trees. As a source of organic fertilizer to regulate the balance between supply and demand of nitrogen and promote agricultural production. The research and utilization of nitrogen-fixing species gradually attracted people’s attention (Bo-nd, 1976; Sprent, 1979). Purple soil is the main soil in the Sichuan Basin. The coverage of forest vegetation in this area is low and water and soil are the most abundant